TY - JOUR
T1 - Interactive comorbidity between opioid drug abuse and HIV-1 Tat
T2 - Chronic exposure augments spine loss and sublethal dendritic pathology in striatal neurons
AU - Fitting, Sylvia
AU - Xu, Ruqiang
AU - Bull, Cecilia
AU - Buch, Shreya K.
AU - El-Hage, Nazira
AU - Nath, Avindra
AU - Knapp, Pamela E.
AU - Hauser, Kurt F.
N1 - Funding Information:
Supported by The National Institute on Drug Abuse ( P01 DA19398; R01 DA18633; R01 DA24661; K02 DA027374 ).
PY - 2010/9
Y1 - 2010/9
N2 - HIV-1 infection predisposes the central nervous system to damage by opportunistic infections and environmental insults. Such maladaptive plasticity may underlie the exaggerated comorbidity seen with HIV-1 infection and opioid abuse. Although morphine and HIV-1 Tat synergize at high concentrations to increase neuronal death in vitro, we questioned whether chronic low Tat exposure in vivo might contribute to the spectrum of neuropathology through sublethal neuronal injury. We used a doxycycline-driven, inducible, HIV-1 Tat transgenic mouse, in which striatal neuron death was previously shown to be absent, to examine effects of differential Tat expression, alone and combined with morphine. Low constitutive Tat expression caused neurodegeneration; higher levels induced by 7 days of doxycycline significantly reduced dendritic spine numbers. Moreover, Tat expression widely disrupted the endogenous opioid system, altering μ and κ, but not δ, opioid receptor and proopiomelanocortin, proenkephalin, and prodynorphin transcript levels in cortex, hippocampus, and striatum. In addition to markedly reducing spine density by itself, morphine amplified the effect of higher levels of Tat on spines, and also potentiated Tat-mediated dendritic pathology, thus contributing to maladaptive neuroplasticity at multiple levels. The dendritic pathology and reductions in spine density suggest that sustained Tat ± morphine exposure underlie key aspects of chronic neurodegenerative changes in neuroAIDS, which may contribute to the exacerbated neurological impairment in HIV patients who abuse opioids.
AB - HIV-1 infection predisposes the central nervous system to damage by opportunistic infections and environmental insults. Such maladaptive plasticity may underlie the exaggerated comorbidity seen with HIV-1 infection and opioid abuse. Although morphine and HIV-1 Tat synergize at high concentrations to increase neuronal death in vitro, we questioned whether chronic low Tat exposure in vivo might contribute to the spectrum of neuropathology through sublethal neuronal injury. We used a doxycycline-driven, inducible, HIV-1 Tat transgenic mouse, in which striatal neuron death was previously shown to be absent, to examine effects of differential Tat expression, alone and combined with morphine. Low constitutive Tat expression caused neurodegeneration; higher levels induced by 7 days of doxycycline significantly reduced dendritic spine numbers. Moreover, Tat expression widely disrupted the endogenous opioid system, altering μ and κ, but not δ, opioid receptor and proopiomelanocortin, proenkephalin, and prodynorphin transcript levels in cortex, hippocampus, and striatum. In addition to markedly reducing spine density by itself, morphine amplified the effect of higher levels of Tat on spines, and also potentiated Tat-mediated dendritic pathology, thus contributing to maladaptive neuroplasticity at multiple levels. The dendritic pathology and reductions in spine density suggest that sustained Tat ± morphine exposure underlie key aspects of chronic neurodegenerative changes in neuroAIDS, which may contribute to the exacerbated neurological impairment in HIV patients who abuse opioids.
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U2 - 10.2353/ajpath.2010.090945
DO - 10.2353/ajpath.2010.090945
M3 - Article
C2 - 20651230
AN - SCOPUS:77956544206
SN - 0002-9440
VL - 177
SP - 1397
EP - 1410
JO - American Journal of Pathology
JF - American Journal of Pathology
IS - 3
ER -